Piano-action.



1' UNITED P TENT OFFICE.

ROBERT OPPITZ, OF KOBLENZ, GERMANY.

PIANO-ACTION.

Improvements in Piano-Actions, of which the following is aspecification.

This invention relates to a piano-action provided with a repetitionspring arranged. on the upper part of the jack, and so con structed thatthe adjustment of the power of the said spring can be effectedindependent of the adjustment of the regulating button on thecounter-check which determines the distance that the hammer falls. Thisobject is accomplished by inserting the spring into a slot of the jack,so that it has always a fixed fulcrum in the jack, whereby its free armwhich acts upon the hammer has always the same position relatively tothe jack, the adjustment of the power of the spring being effected bymeans of its other arm. The adjustment of the distance through which thehammer is to recede from the string is effected independently of therepetition spring by means of the adjusting button mounted on thecounter-check and under which the spring engages after the keyhas beenstruck. In this way the hammer is always sustained ready for action,even during repeating, as the distance through which the hammer is tofall back may be readily adapted to all requirements without changingthe power of the repetition spring.

In the accompanying drawing: Figure 1 is a side elevation of a pianoaction embodying my invention, showing the normal position of the parts;Fig. 2 is a similar view, showing the position of the parts after thekey has been lightly struck; Fig. 3 a similar view, showing the positionof the parts when the key has been forcibly struck, and Fig. 4 a detailof part of the jack, showing the repetition spring in position.

When the key a, is struck, the wippen b, is raised in known manner andthe hammer e, is brought against the string 8, by engagement of the jack0, with the hammer-butt d, pivoted at 90. The repetition spring g,mounted on the upper part of the jack, has the position shown in Fig. 1,relatively to the Specification of Letters Patent.

Application filed February 16, 1907.

Patented June 9, 1908.

Serial No. 357,661.

counter-check h, in the normal position of the action.

WVhen the key is lightly struck, the repetition spring g, engagesbeneath the adjustable button f, of the counter-check and prevents thehammer from completing its full return movement; at the same time thejack c, is moved towards the button f, by contact of its tail m, withbutton Z, (Fig. 2). hen the key has been heavily struck, spring g, willbe so bent that counter-check 7t, engages backcheck 1, while the jackengages with the upper notch in. the hammer-butt, (Fig. 3). Button f,can be raised or lowered by turning its screw spindle i, which works inthe counter-check h, so that the return of the hammer can be regulated.

When the finger is raised ever so little from the key, whether the touchhad been light or heavy, the hammer e, is freed and is driven upwards byspring g; the jack 0, and the spring g, remain first in the positionassumed when the key was struck, while the hammer itself is merelyraised by the spring In this way the aok c, which is moved backwards bya helical spring n, acting on its tail m, can engage beneath thehammer-butt, so that the hammer is again ready to be actuated. Thesemovements occur as already stated, by the slightest raising of thefinger off the key and without the necessity of with drawing the biggercompletely.

The repetition spring g, is preferably made of the form shown in Fig. 4,so that its tension can be adjusted in a simple manner. It is bent at p,and engages in a rearwardly narrowing recess or slot 0, of jack 0. Bypushing the spring into or partly withdrawing it from slot 0, its powermay be readily altered without changing the elevation of its operativeend in relation to the jack 0, as indicated. by dotted lines in Fig. 4.

I claim:

1. A piano action provided with a jack, a spring carried thereby, meansfor adjusting the power of the spring, a counter-check, and a regulatingbutton carried thereby and lo cated so as to be engaged by the spring,substantially as specified.

2. A piano action provided with a slotted jack, a bent spring seatedtherein and having my name in the presence of two subscribing an upperand a lower arm, means for achustw1tnesses. mg the power of the upperarm, a counterl J check, and a regulating button carried there- ROBERTO1 PIrl/J' 5 by and loeateclso as to be engaged by the Utnesses:

upper spring-arm, substantially as specified. BESSIE F. DUNLAP,

in Witness whereof, I have hereunto signed 'l'JoUIs 'VANDoRP.

